JPH0844309A - High-frequency deflecting yoke drive circuit - Google Patents

Abstract

PURPOSE:To provide a high-frequency deflecting yoke drive circuit which gives a specified driving sensitivity by setting the inductance of the deflecting yoke large. CONSTITUTION:One terminal of the deflecting yoke 7 is impressed with a positive deflecting voltage caused by the primary coil 5 of a deflecting transformer and the other terminal is impressed with the negative deflecting voltage which is caused by the secondary coil of the deflecting transformer in correspondence to the positive deflecting voltage. Consequently the deflecting yoke 7 can be impressed with a deflecting voltage larger than the positive deflecting voltage which is established under a specified source voltage, a specified deflecting frequency and the dielectric withstand voltage of the horizontal switching element 1 and, through this, the inductance of the deflecting yoke can be established that much larger, increasing the design freedom to improve the convergence characteristics and reducing heat emission because of a smaller deflecting current. In addition, the deflecting current can be adjusted by varying the coupling between the primary- and secondary coils. Furthermore the distribution capacity of the deflecting yoke 7 to ground can be reduced and the parasitic oscillation is attenuated too.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency deflection yoke drive circuit used in displays and the like.

[0002]

2. Description of the Related Art In recent years, a horizontal deflection circuit using a flyback transformer or a deflection yoke has become higher in frequency so that the horizontal deflection frequency becomes 2 to 6 times higher than that of television broadcasting due to higher image quality and higher density display. I'm out.

A deflection yoke drive circuit using a conventional flyback transformer or deflection yoke will be described below with reference to the drawings. FIG. 2 is a circuit diagram showing the configuration of a conventional deflection yoke drive circuit. In the figure, 9 is a switching element, 10 is a damper diode, 11 is a resonance capacitor, 12 is a primary winding of a deflection transformer, 13 is a power supply, 14 is a deflection yoke, and 15 is an S-shaped correction capacitor.

The mutual relationship and operation of the above-mentioned components will be described. When the switching element 9 is turned on, energy is supplied through the primary winding 12 of the deflection transformer, and a positive deflection current substantially proportional to time flows through the deflection yoke 14. Next, when the switching element 9 is turned off, the combined inductance component of the primary winding 12 of the deflection transformer and the deflection yoke 14 and the capacitance component of the resonance capacitor 11 resonate, and the deflection current sharply moves in the opposite direction. When the voltage across the resonance capacitor 11 becomes zero or less, the damper diode 10 is turned on to dump the resonance, and when the switching element 9 is turned on next time, a positive deflection current flows again. Horizontal deflection is continued by repeating this operation.

Now, the deflection current is IDY, the power supply voltage is B, the horizontal period is TH, the retrace line period is TF, and the L value of the deflection yoke is LDY.
Then, IDY = B. (TH-TF) / LDY On the other hand, the VCP generated in the collector of the switching element at this time is VCP = B. [{(TH / TF) -1}. (Π / 2) +1] It is represented by. The deflection capability is indicated by the value of deflection sensitivity = LDY · (IPP) ^2, but the deflection current amplitude IPP is VCP.
Since it is proportional to / LDY, the deflection sensitivity is VCP ² / LDY = VCP
・ Proportional to IDY.

[0006]

In such a conventional deflection yoke drive circuit, the value of the horizontal period TH is specified to be a small value by increasing the deflection frequency, and the deflection pulse voltage given by the equation of VCP is given. The value of is regulated by the withstand voltage of the switching transistor which is a switching element, so that the value of the blanking period TF is inevitably determined under the predetermined power supply voltage B. Under such conditions, it is no exaggeration to say that the value of the deflection current IDY is determined only by the inductance of the deflection yoke, as is clear from the above equation of IDY. Now, in order to obtain a predetermined deflection sensitivity by increasing the screen size, it is necessary to set a large value of the deflection current IDY, and it is necessary to set the inductance of the deflection yoke to be extremely small. For example, the calculation examples are shown below at 15.75 KHz and 64 KHz. Assuming that VCP is 1500V, 15.75KHz, pulse width = 12.0μsec, B = 194V, L
DY = 2.85mH 64 KHz, pulse width = 3.0μsec, B = 197.5V, LDY
= 179 μH, so the inductance must be set to be extremely small.

As described above, when the inductance is set small, the number of turns of the coil decreases due to the structure of the deflection yoke,
The degree of freedom in adjusting the magnetic field distribution, that is, adjusting the winding position of the conducting wire, is reduced, which is a factor that significantly deteriorates the image quality conversion characteristic. In addition, the large deflection current causes large heat generation, and the deflection coil is designed. In the above situation, there is a problem in that a predetermined magnetic field distribution is realized and the problem of heat generation is solved, which is a problem contradictory to higher performance.

The present invention is intended to solve the above-mentioned problems, and the inductance of the deflection yoke can be set larger than before under a given power supply voltage, withstand voltage of the switching element and horizontal drive frequency. Easy to adjust and improve the convergence characteristics,
An object of the present invention is to provide a high-frequency deflection yoke drive circuit that can reduce the deflection current and improve the heat generation characteristics.

[0009]

In order to achieve the above object, the present invention provides a horizontal deflection circuit in which one end of a primary winding of a deflection transformer is connected to a power source and the other end is connected to a switching element. A positive deflection voltage is generated by turning the switching element on and off and is applied to one end of the deflection yoke, and a negative deflection voltage corresponding to the positive deflection voltage is generated with respect to the ground potential. A deflection circuit is configured by applying a deflection voltage to the other end of the deflection yoke, and the deflection voltage applied to both ends of the deflection yoke is made larger than the positive deflection voltage, thereby making the inductance of the deflection yoke positive. The high-frequency deflection yoke drive circuit can be set larger than when only the deflection voltage is applied.

[0010]

According to the present invention, in the above construction, a positive deflection voltage by the primary winding of the deflection transformer is applied to one end of the deflection yoke, and a negative deflection voltage is applied to the other end of the deflection yoke. Under the positive deflection voltage of, the magnitude of the deflection voltage applied to the deflection yoke becomes (positive deflection voltage + negative deflection voltage) and increases by the amount of the negative deflection voltage. When it is realized, the deflection current can be reduced by that amount, so that the inductance of the deflection yoke can be set larger than that when only the positive deflection voltage is applied. Further, when a negative deflection voltage is obtained by the secondary winding provided in the deflection transformer, the deflection current can be adjusted by adjusting the degree of coupling between the primary and the secondary even if the number of windings is small.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a high frequency deflection yoke drive circuit of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing the configuration of this embodiment. In the figure, 1 is a horizontal switching element, 2 is a damper diode, 3 is a resonance capacitor, 4 is a power supply, 5 is a primary winding of a deflection transformer, 6 is a secondary winding of the deflection transformer, 7 is a deflection yoke, and 8 is a deflection yoke.
Is an S-th capacitor.

The mutual relationship and operation of the above components will be described. As described above, the deflection current is formed by turning the horizontal switching element 1 on and off, but in the present invention, the deflection transformer is provided with the primary winding 5 and the secondary winding 6 which are independently separated. One end is grounded so as to be coupled with the secondary winding 5 and generate a negative deflection pulse. One end of the deflection yoke 7 is connected to the collector portion of the horizontal switching element 1,
The other end is connected to the negative deflection pulse generation terminal of the secondary winding 6. Now, the winding ratio of the primary winding 5 and the secondary winding 6 of the deflection transformer is set to 1: n. In the above configuration, when the horizontal switching element 1 is in the ON state, the deflection current in the positive direction due to the power supply voltage B and the secondary voltage n · B flows in the deflection yoke 7, and from the time when the horizontal switching element 1 is turned off, A negative resonance current flows due to the combined inductance of the deflection transformer and the deflection yoke 7 and the capacitance of the resonance capacitor 3, and when the voltage across the resonance capacitor 3 turns negative, the damper diode 2 turns on and resonance occurs. Dumped,
Next, the horizontal switching element 1 is turned on, and the operation again shifts to the flow of the positive deflection current. The horizontal deflection operation is executed by repeating the above operation.

In this operation, one end of the primary winding 5 of the deflection coil is connected to the power supply 4 to generate a deflection voltage as in the conventional case, so that the positive deflection pulse voltage VCP is applied to the horizontal switching element 1. It can be set according to the breakdown voltage. On the other hand, a total voltage of the positive deflection voltage and the negative deflection voltage by the secondary winding 6 is applied to the deflection yoke, and in terms of deflection pulse voltage, VCP + n · VCP = (1
+ N) -VCP voltage is applied. Therefore, a deflection voltage (1 + n) times the positive deflection voltage determined by the breakdown voltage of the switching element 1 can be applied to the deflection yoke 7. To obtain a predetermined deflection sensitivity, set the deflection voltage to (1+
It goes without saying that the inductance may be (1 + n) ² times when given n times. In this way, the total voltage of the positive deflection voltage from the primary winding 5 and the negative deflection voltage from the secondary winding 6 is applied to the deflection yoke 7, and the positive deflection voltage is determined by the breakdown voltage of the switching element 1. The inductance of the deflection yoke can be set larger than that of the related art by setting the voltage to. Further, since the deflection current is reduced by the amount of the increased inductance, heat generation due to current loss in the deflection yoke is also reduced.

Further, during the deflection operation, the deflection yoke 7
As shown in FIG. 3 (b), the deflection voltage applied to is divided into positive and negative of 1: n with respect to the ground, so that there is an electric neutral point at the position of the winding ratio 1: n. , The distributed capacitance of the deflection yoke with respect to ground is equivalent to 1 / (1+) due to the change in the potential distribution as compared with the conventional case shown in FIG.
n) ^2, and also has the effect of reducing the parasitic vibration component in the vibration circuit after the blanking period.

FIG. 4 is an equivalent circuit diagram showing the coupling between the deflection transformer and the deflection yoke 7 connected to the secondary winding 6.
In the figure, the deflection current is the leakage inductance 21.
The deflection current can be adjusted by adjusting the value of k, and the degree of coupling can be adjusted even when the winding number of the deflection yoke is small and proper winding adjustment is difficult. This allows the deflection yoke to be adjusted.

As described above, according to this embodiment, a predetermined positive deflection voltage determined by the breakdown voltage of the switching element and 2
By applying a negative deflection voltage from the next winding to the deflection yoke, the deflection yoke inductance can be set large, heat generation can be reduced, and the degree of coupling can be adjusted to facilitate adjustment of the deflection yoke. It is also possible to equivalently reduce the distributed capacitance with respect to ground to reduce parasitic vibration.

In the embodiment, the negative deflection voltage is realized by the secondary winding of the deflection transformer, but it goes without saying that other equivalent means may be used.

[0018]

As is apparent from the above description, according to the present invention, in the horizontal deflection circuit, one end of the primary winding of the deflection transformer is connected to the power supply and the other end is connected to the switching element, and the switching element is connected. Is turned on and off to generate a positive deflection voltage, which is applied to one end of the deflection yoke, and a negative deflection voltage corresponding to the positive deflection voltage is generated with respect to the ground potential. The deflection circuit is configured by applying the deflection voltage to the other end of the deflection yoke, and the deflection voltage applied to the both ends of the deflection yoke is made larger than the positive deflection voltage, whereby the inductance of the deflection yoke is increased to the positive deflection voltage. By setting it so that it can be set larger than when only applying it, a deflection voltage larger than the deflection voltage limited by the breakdown voltage of the switching element is applied to the deflection yoke. In that case, the inductance of the deflection yoke can be set to a correspondingly large value, so the degree of freedom in designing the deflection yoke can be increased to improve the convergence characteristics, heat generation can be reduced, and when a negative deflection voltage is obtained by the transformer, By adjusting the degree, the deflection current can be easily adjusted. It also has the effect of reducing the parasitic capacitance by reducing the distributed capacitance to earth.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a high-frequency deflection yoke drive circuit of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a conventional deflection yoke drive circuit.

FIG. 3 is a characteristic diagram showing the relationship between the ground voltage of the deflection yoke and the distributed capacitance.

FIG. 4 is an equivalent circuit diagram of the present invention.

[Explanation of symbols]

1 Horizontal switching element (switching transistor) 2 Damper diode 3 Resonant capacitor 4 Power supply 5 Primary winding of deflection transformer 6 Deflection transformer secondary winding for generating negative deflection voltage 7 Deflection yoke 8 S-shaped capacitor

Claims (3)

[Claims] 1. In a horizontal deflection circuit, one end of a primary winding of a deflection transformer is connected to a power source, the other end is connected to a switching element, and a positive deflection voltage is generated by turning on / off the switching element. While applying to one end of the deflection yoke, a negative deflection voltage corresponding to the positive deflection voltage is generated with respect to the ground potential, and the negative deflection voltage is applied to the other end of the deflection yoke to form a deflection circuit. A high-frequency wave which is configured so that the deflection voltage applied to both ends of the deflection yoke is made larger than the positive deflection voltage, so that the inductance of the deflection yoke can be set larger than that when only the positive deflection voltage is applied. Deflection yoke drive circuit. 2. A deflection transformer provided with a negative deflection voltage.
The high-frequency deflection yoke drive circuit according to claim 1, wherein the high-frequency deflection yoke drive circuit is obtained by a secondary winding. 3. The high frequency deflection yoke drive circuit according to claim 2, wherein the deflection current of the deflection yoke is adjusted by the degree of coupling between the secondary winding and the primary winding.